#include<bits/stdc++.h>
using namespace std;

int main() 
{
    int n;
    cin>>n;
    
    for (int t = 0; t < n; t++) 
	{
        int k;
        string s;
        cin >> k >> s;
        int ans = 0;
        int i = 0;
        while (s[i]) 
		{  
            int d;
            if (s[i] <= '9')
			{
				d = s[i] - '0';
			}
            else
			{
				d = s[i] - 'A' + 10;
        	}
            ans = ans * k + d;
            i++;
        }
    	cout<<ans<<"\n";
    }
    return 0;
}